Topeka  The Kansas Supreme Court on Friday gave its approval of a permit that would allow two utility companies to build a large new coal-fired power plant in southwest Kansas, dealing a blow to environmental groups that had hoped to block the construction.

In a long-awaited opinion, the court said the Kansas Department of Health and Environment acted properly in 2010 when it issued a revised permit for Sunflower Electric Cooperative, based in Hays, and the Denver-based Tri-State Generation and Transmission Association to build a new, 895 megawatt coal-fired generating unit next to an existing plant near Holcomb, about seven miles west of Garden City.

That proposed plant has been the focal point of debate in Kansas over the issue of climate change. The Kansas Sierra Club has been trying to block permitting of the plant for more than a decade, arguing that it would add significant amounts of greenhouse gas emissions and other pollutants to the atmosphere, in violation of federal clean air regulations.

While the case has been pending before the court, former President Barack Obama’s administration enacted even more regulations, known as the Clean Power Plan, aimed at reducing carbon emissions from power plants in the United States.

Friday’s decision comes at the same time that newly elected President Donald Trump’s administration is attempting to roll back or completely repeal those regulations. But it also comes at a time when new coal-fired generation has become less economically viable as the cost of from wind and other renewable energy sources has come down.

Elizabeth Katt Reinders, of the national Sierra Club organization, agreed that the plant has become less economically feasible since the litigation began.

“The overwhelming trend is that coal is on its way out, and clean energy is taking its place,” Reinders said in a statement emailed to news organizations. “In 2016, 63 (percent) of all new power generation was clean energy. Since the Holcomb plant was proposed, the cost of clean energy has plummeted.”

In a statement posted on Sunflower’s website, the company did not specifically say whether it planned to move forward with the project.

“Just as it would have been ten years ago when we began this process, the Court’s decision is another incremental step in the process,” the company said. “Sunflower and Tri-State will continue to assess the project relative to other resources to meet the long-term power needs of our Member co-ops.”

Amanda Goodin, an attorney for Earthjustice, the legal team that represented the Sierra Club in the case, said she doubts whether Sunflower and Tri-State would still be able to find financing for the roughly $3 billion construction project, despite the different direction that the Trump administration has taken on climate change regulations.

“To make this profitable, they’ve got to want it not just for a few years, but for decades and decades,” she said in a phone interview from Seattle. “I’ll be the first to tell you that under this federal administration, it sure doesn’t look like we’re going to make a lot of progress on climate change. But they need to bet not just on this president ignoring the reality of climate change. They need to bet on the country ignoring that reality for decades and decades and decades to come, and letting them to emit unchecked well into the future. And if I were looking to put $3 billion down on a project, I’m not sure that’s a bet I would take.”

In 2007, during Democratic Gov. Kathleen Sebelius’ administration, KDHE became the first state regulatory agency to cite greenhouse gas emissions as a reason for denying a permit to build a coal-fired power plant. The case of the Holcomb plant has been tied up in court ever since.

At the time, Sunflower and Tri-State were seeking to build two 700-megawatt generating units at the site.

Sebelius left office in 2009 to become Obama’s Secretary of Health and Human Services. Her successor, Mark Parkinson, later cut a deal to approve a permit for a single 895-megawatt unit.

Goodin said that even at that smaller size, the new Holcomb plant would be, by far, the largest source of greenhouse gas emissions in the state, producing an estimated 8 million tons a year of carbon dioxide and other pollutants.

The Kansas Sierra Club, with other environmental groups, challenged that permit, saying KDHE had failed to comply with federal Clean Air Act regulations regarding one-hour emission limits on two kinds of pollutants, nitrogen dioxide and sulfur dioxide. In 2010, the Kansas Supreme Court agreed and remanded the issue back to KDHE with directions to apply the one-hour limits.

KDHE responded by adding an addendum to the previous permit. But the Sierra Club and Earthjustice challenged that decision, arguing that KDHE should have opened an entirely new permitting process, incorporating new regulations on mercury and other air toxins that the EPA had issued while the case was being litigated.

In its decision Friday, the court rejected that claim, saying the plaintiffs had failed to prove that KDHE had violated federal regulations by issuing the permit addendum.